As computer-based systems, such as monitoring systems, training systems, game consoles, appliances, personal computers (“PCs”), servers, personal digital assistants (“PDAs”), cellular phones, become more prevalent in recent years, intuitive human-machine communications have become increasingly important. Human-machine communications generally can be categorized into user interface device and machine interface device, wherein user interface device provides a mechanism for a user to talk to a machine while machine interface device is a mechanism for a machine to talk to a user. Many conventional user interface devices have been well developed over the years, such as keyboard, voice recognition, touch panel, joystick, and the like. Machine interface, however, is typically limited to audible cues and visual cues.
An audible cue typically is a sound or voice initiated by a machine or a computer to notify or to respond to a user's request(s). For example, audible cues may be a beep, a voice, a ring, etc. and it is used to remind, acknowledge, and/or warn the user(s). Audible cues have been effectively used by the machines to communicate with the user(s). For example, a machine initiates a beep when a user tries to choose a menu item that is currently not available.
A visual cue typically includes a graphical cue or a textual cue enabling a machine to communicate to a user. Visual cues typically allow users to see the results of their interaction with the machine or computer immediately. For example, when a user clicks to open a file, the computer responds to user's click by providing context of the file in a text format on the display. Graphical cues typically assist and/or indicate user actions. For example, a cursor on a screen is a graphical cue to indicate or assist user action.
A problem associated with machine interface is that audible cues are not effective in certain scenarios while visual cues may not be available in some occasions. For example, a marathon runner may have a difficult time noticing visual cues via a display. Also, the runner may not be able to notice audible cues in a noisy environment.